Description: The Animal Core will support and facilitate the research in all projects by providing the animals needed and housing the animals during experiments. Animals provided and maintained include normal rats, various strains of mice, transgenic mice, knockout mice and rabbits for immunization. In addition, the core will produce requested transgenic and mutant mice for investigators; perform stereotaxic third ventricle canulations for administration of antisense oligonucleotides; and cryopreserve, maintain and reimplant embryos from mutant mice as needed. Specific services include embryo isolation, purification of DNA fragments for microinjection, microinjection of DNA fragments into the male pronucleus, reimplantation into pseudopregnant recipient females, transfer of ES cells to blastocysts, cross breeding of progeny, isolating and characterizing the DNA from tails of weanling mice for genotyping, embryo freezing and thawing, management of the colony and record keeping.